Implement Database

[nickdibari]

Currently the leaderboard data is written to a CSV file after retrieving the commit records from Github. It would be better to utilize a database for this functionality, to increase performance and avoid files cluttering the working directory. Suggest this be written in SQLite, because it's the simplest to spin up and has a standard library module for Python.

Schema would represent the Dev model, with a Username, Avatar, Commits, and Hash
Consider changing hash attribute to a repo URL, which would accomplish the same idea you have and also be more readable if you decide to expand to multiple repositories

SQLite docs for Python: https://docs.python.org/2/library/sqlite3.html

[nickdibari]

With the usage of the Flask web framework, suggest using Flask's database API.

Flask Database Tutorial: https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-iv-database